System for loading ships at sea

Abstract

This invention relates to a system for loading or unloading a ship at sea, in particular for operations in connection with oil and gas activity, whereby the ship concerned is equipped with a mooring device at its bow. There is included an anchor device located at the seabed, and at least one anchoring line adapted to connect the anchor device to the mooring device on the ship. A permanent anchor device is provided with a swivel device for the anchoring line, and a buoyant body is attached to a middle portion of the anchoring line. Moreover, there is provided a hose connected to the swivel device and to the ship, for loading or unloading operations.

What is claimed is: 
     
       1. System for loading or unloading ships at sea, in particular for operations in connection with oil and gas activity, whereby the ship concerned is equipped with a mooring device, and where there is included an anchor located at the seabed and being in fluid communication with a subsea installation, as well as at least one anchoring line adapted to connect said anchor to said mooring device on the ship, comprising: a permanent anchor device as said anchor, said permanent anchor device being provided with a swivel device for said anchoring line,   wherein a lower portion of said anchoring line is designed with a crowfoot connected to said swivel device,   a buoyant body attached to a middle portion of the anchoring line, and   a hose the lower end of which is connected to said swivel device and the upper end of which is adapted to be connected to a fluid connection unit on said ship.   
     
     
       2. System according to claim 1, wherein the said permanent anchor device is chosen from the group consisting of a suction anchor, a gravitation anchor, and a pile anchor. 
     
     
       3. System according to claim 1, wherein said swivel device comprises two cantilevered arms having outer ends to which the lines of said crowfoot are attached. 
     
     
       4. System according to claim 1, wherein said hose is provided with buoyancy elements. 
     
     
       5. System according to claim 1, wherein the hose is separated into more than one hose at least one of which is connected to said buoyant body, at least one of which is connected to said anchor, and at least one of which is connected to said mooring device. 
     
     
       6. System according to claim 2, wherein the lower end of said hose is connected centrally at said swivel device. 
     
     
       7. System according to claim 6, wherein said hose during substantially all anchoring conditions extends from said swivel device at a more horizontal angular position than the angular position of the lower portion of said anchoring line. 
     
     
       8. System according to claim 1, wherein said hose as a result of its length and exerted buoyancy is adapted to extend through the water underneath said anchoring line. 
     
     
       9. System according to claim 3, wherein the crowfoot is pivotable about an axis between the cantilevered arms. 
     
     
       10. System according to claim 6, wherein the said hose extends from swivel device centrally between the crowfoot lines. 
     
     
       11. An anchor for installation at the seabed for mooring, loading or unloading of ships or other vessels, in connection with oil and gas activity at sea, comprising a swivel device provided with attachment members for at least one anchoring line from the ship, whereby a rotation axis of said swivel device is adapted to be approximately vertical at the seabed thereby allowing the swivel device to rotate in a plane approximately parallel to the seabed, and whereby said swivel device comprises a swivel member for a fluid hose and a through-going fluid passage adapted to be connected to an installation at the seabed, and wherein said attachment members comprise two cantilevered arms having outer ends for attachment of anchoring lines; wherein a lower anchor part on one hand and substantially all other parts on the other hand, including said swivel device are separable by means of detachable joining elements, so that the other parts can be retrieved to the surface for maintenance, repair or replacement. 
     
     
       12. Anchor according to claim 9, wherein said attachment members are adapted to be located at a lower level than said swivel member in operative position at the seabed. 
     
     
       13. Anchor according to claim 11, comprising a force transferring main member having a radial projection which carries said attachment members, and at least one supporting roller connected to said main member and located essentially underneath said projection and being adapted to roll in a guide at the top of a lower anchor member. 
     
     
       14. Anchor according to claim 11, comprising a plate or frame like base member resting on top of the actual anchor member and separable therefrom, that said base member is provided with a carrier member for said swivel device, and   that said base member carries a connector for a pipeline from an installation at the seabed.   
     
     
       15. Anchor according to claim 14, wherein said connector is adapted to make possible connection and disconnection of said pipeline. 
     
     
       16. Anchor according to claim 14, comprising an outer swivel housing which is arranged to be rotatable in relation to said anchor member and which carries said connection member, and   a journal device for said swivel housing which is adapted to transfer bending forces being due to a connected fluid hose and possibly an anchoring line to said anchor member, through said carrier member and base member.   
     
     
       17. Anchor according to claim 11, comprising a yoke having two legs the outer ends of which are pivotably connected to said attachment members being located at either side of said swivel device, and that the opposite end of said legs are adapted to be connected to an anchoring line. 
     
     
       18. Anchor according to claim 11, wherein the said anchor is chosen from the group consisting of a suction anchor, gravitation anchor, and a pile anchor. 
     
     
       19. Method for installation of an anchor characterized by swivel device provided with attachment members for at least one anchoring line from the ship, whereby a rotation axis of said swivel device is adapted to be approximately vertical at the seabed, and whereby said swivel device comprises a swivel member for a fluid hose and a through-going fluid passage adapted to be connected to an installation at the seabed in a system according to claim 1, wherein said anchor is suspended at the end of an anchor chain or wire belonging to a generally regular anchor capstan or winch of the ship concerned, being employed for lowering the anchor to a predetermined point at the seabed.